The present invention relates to a telemetering system, in particular, one disposed in a drillpipe.
The conventional manner of drilling a borehole comprises lowering a drill bit into the earth, the drill bit being powered, for instance, by the rotation of the drillpipe, or by fluids circulating through the drillpipe and thence back up to the surface through the space between the drillpipe and the borehole. The drillpipe is made up of sections, new sections being added periodically at the top of the drill string to allow the drill bit to be lowered further.
Much useful data can be garnered from sensors included in the drillpipe, such as temperature and pressure. To retrieve this information at the surface requires some form of media to transmit it through. Known systems include using pressure waves through the circulating mud, and electromagnetic pulses. Better rates of transfer and less attenuation may be achieved however by using an electrical conducting element.
The simplest way of installing a conducting cable, or indeed any line, along the drill string is to wait until drilling has ceased and lower a single length down the drill string. Where it necessary to take readings from instrumentation means before the drillpipe is completed however, the cable must be lowered into the drill string, only to be withdrawn each time a new drillpipe section is added to the drill string.
One known method comprises a drillpipe incorporating conducting elements. The conducting elements of adjoining sections of drillpipe are electrically connected by sliding contacts, Such a system is expensive, and liable to develop faults as a result of fluid contaminating the connection. Many telemetry systems rely upon a segmented cable running through the drillpipe, cable sections being added in order to allow fresh sections of drillpipe to be added.
Every connection between individual lengths of cable provides a further opportunity for faults to occur.
The object of the present invention is to provide an apparatus and method for disposing reliable telemetric equipment in drillpipes and the like in an efficient manner.
According to the present invention there is provide a drillpipe line installation system, the drill string being composed of drillpipe sections which are added and removed to increase and decrease the length of the drillpipe, wherein a length of cable is disposed within the drill string, the length of this cable being greater than that of the drill string at the time the cable is disposed, there being a lower cable storage means for stowing the cable in a compact manner and paying out the cable when the length of the drillpipe is increase, and an upper cable storage means which can take up the cable in a compact manner when the length of the drillpipe is decreased.
Preferably the lower cable store means is a bobbin upon which the cable is wound. Preferably the upper cable store means is a bobbin upon which the cable is wound. The cable may include a wireless transmitter capable of transmitting signals to a signal receiver. The cable may be releasably connected to a connector at its top, the cable being disconnected from the connector when a drillpipe section is to be added or removed, threaded through the drillpipe section before being reconnected to the connector, the cable including a wireless transmitter, such that signals carried by the cable can be transmitted by the wireless transmitter to be received by a signal receiving means.
According to another aspect of the present invention, there is provided a method of installing a line along a drill string or the like, the drill string being composed of drillpipe sections which are added as the drillpipe progresses, a length of cable being disposed within the drill string before the string has reached its final length, the length of this cable being greater than that of the drill string at the time the cable is disposed, the cable being releasably connected to a connector at its top, the cable being disconnected from the connector when a drillpipe section is to be added or removed, threaded through the drillpipe section before being reconnected to the connector, the cable including a wireless transmitter, such that signals carried by the cable can be transmitted by the wireless transmitter to be received by a signal receiving means.
According to a further aspect of the present invention, there is provided a method of installing a line along a drill string or the like, the drill string being composed of drillpipe sections which are added as the drillpipe progresses, a length of cable being disposed within the drill string before the string has reached its final length, the length of this cable being greater than that of the drill string at the time the cable is disposed, the cable being releasably connected to a connector at its top, the cable being disconnected from the connector when a drillpipe section is to be added or removed, threaded through the drillpipe section before being reconnected to the connector, the top of the cable being secured relative to the drillpipe after being disconnected, and reconnected by lowering the connector through the drillpipe to the top of the cable.
According to a further aspect of the present invention, there is provided a method of installing a line along a drill string or the like, the drill string being composed of drillpipe sections which are added as the drillpipe progresses, a length of cable being disposed within the drill string before the string has reached its final length, the length of this cable being greater than that of the drill string at the time the cable is disposed, the cable being releasably connected to a connector at its top, the cable being disconnected from the connector when a drillpipe section is to be added or removed, threaded through the drillpipe section before being reconnected to the connector, the cable is supported by an anchor that can be displaced upwards through the drillpipe, but which resists downward displacement through the drillpipe.
According to a further aspect of the present invention, there is provided a method of installing a line along a drill string or the like, the drill string being composed of drillpipe sections which are added as the drillpipe progresses, a length of cable being disposed within the drill string before the string has reached its final length, the length of this cable being greater than that of the drill string at the time the cable is disposed, the cable being releasably connected to a connector at its top, the cable being disconnected from the connector when a drillpipe section is to be added or removed, threaded through the drillpipe section before being reconnected to the connector, the top of the cable being secured by a tractor inside the drillpipe, the tractor capable of ascending and descending through the drillpipe when the cable is disconnected from the connector.
According to a further aspect of the present invention, there is provided a drillpipe line installation system, the drill string being composed of drillpipe sections which are added and removed to increase and decrease the length of the drillpipe, wherein a length of cable is disposed within the drill string, the length of this cable being greater than that of the drill string at the time the cable is disposed, the excess cable being stored wound upon a mandrel, the cable wound upon the mandrel being twisted as it is applied such that when the cable is twisted as the mandrel is unwound, the twisting already applied to the cable untwists.
According to a further aspect of the present invention, there is provided a drillpipe line installation system, the drill string being composed of drillpipe sections which are added and removed to increase and decrease the length of the drillpipe, wherein a length of cable is disposed within the drill string, the length of this cable being greater than that of the drill string at the time the cable is disposed, the excess cable being stored wound upon a mandrel, the cable being wound along substantially the length of the mandrel to a single cable thickness, before winding the cable along the mandrel applying a second cable thickness, and applying silicone elastomer to somewhat secure the first layer of cable to the second layer of cable.
According to a further aspect of the present invention, there is provided a drillpipe line installation system, the drill string being composed of drillpipe sections which are added and removed to increase and decrease the length of the drillpipe, wherein a length of cable is disposed within the drill string, the length of this cable being greater than that of the drill string at the time the cable is disposed, the excess cable being stored wound upon a mandrel, the cable being wound upon itself in an overlapping manner at a particular displacement along the mandrel before the cable is wound at another region of the mandrel.
Preferably the cable is wound upon the mandrel such that exposed turns of the cable have a conical shape. Preferably silicone elastomer is used to secure the turns of the cables.
According to a further aspect of the present invention, there is provided a method of installing a line along a drill string or the like, the drill string being composed of drillpipe sections which are added as the drillpipe progresses, a length of cable being disposed within the drill string before the string has reached its final length, the length of this cable being greater than that of the drill string at the time the cable is disposed, the cable being releasably connected to a connector at its top, the cable being disconnected from the connector when a drillpipe section is to be added or removed, threaded through the drillpipe section before being reconnected to the connector, the cable transmitting signals to the connector by an inductive link.